Don't know if your wife and kids would like it but a favorite of mine is a drive down to Key West. Duval St. is a sight indeed. It's a party town so it's more fun for adults than kids but still well worth a visit if it suits you. My wife an I head down there every year or so when the urge strikes. A couple of days is plenty to cover the whole island unless your a real party person.
Key West used to be a more isolated place. If You've ever wondered what happened to all those 60's era hippies, they're in Key West. Kind of fun, but it's gotten much more commercial in the last 10 years than it used to be.
If you do go, pay attention to where you stay. Check with the hotel itself and ask about "dress code"; at many of the hotels, clothing is optional.
From Orlando down to Key West is about 150 miles I guess, I don't know exactly, I never payed attention to the distance. It's not all that far but it can be a slow trip since it's only a two lane road for the most part once you get into the Keys. The best you can average is maybe 55mph, and watch for cops. Speed traps are everywhere, especially after dark.
You'd want to stay overnight but be warned, it's a bit pricey. I'd stay at the Red Rooster on Rt. 1 on the way into Key West, it's about $75.00/night in the summer (off season there). Stop at the tourst centers on the way down for info and to make reservations.
You can buy a beer at any bar (many are open 24 hours), wander the streets with it, go into another, stay up all night and never see an argument. Every place has entertainment of some sort and some of the bars are real charachers. Try the "Hogs Breath". I've been there many times and have yet to see a cop or have any problem at all. Everyone's very friendly - it's a different culture in some ways. The streets get a bit crowded but there's never any friction.
It's not worth getting up much before 11:00am because nothing happens early. Everyone gathers on the waterfront for sundown celabration. You can buy a drink at any of the rolling bars and to watch the various shows that go on. That's the start of day at Key West, after that, Duval St. livens up and the partying goes on through the night.
It may not be your cup of tea, especially with kids to entertain, but it's fun, and if you out of things to do, consider it.
Al